本文關(guān)鍵詞： 鱗片石墨 高壓堿浸 常壓酸浸 熱力學(xué) 提純　出處：《昆明理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：石墨由于其獨(dú)特的晶體結(jié)構(gòu)而具有許多優(yōu)異的物理化學(xué)性能,高純石墨作為石墨的深加工產(chǎn)品在高級密封、復(fù)合材料、核工業(yè)、航空航天等領(lǐng)域也大放異彩。本文首先對石墨的結(jié)構(gòu)性質(zhì)及石墨的應(yīng)用進(jìn)行了概述,指出目前一些重要工業(yè)部門快速發(fā)展和高品質(zhì)石墨短缺的矛盾�？偨Y(jié)了目前世界范圍內(nèi)的石墨提純技術(shù)和工業(yè)生產(chǎn)狀況,提出天然鱗片石墨精礦制備高品位石墨的研究方向,最終提出了本文的主要研究內(nèi)容及研究意義。論文以青島日來石墨有限公司提供的天然鱗片石墨精礦作為研究對象,研究了鱗片石墨中灰分雜質(zhì)的賦存狀態(tài)和脫灰過程的熱力學(xué),據(jù)其提出了高壓堿浸聯(lián)合常壓酸浸法提純石墨的技術(shù)路線,并對提純過程的部分反應(yīng)機(jī)理進(jìn)行了理論分析。利用現(xiàn)代分析測試技術(shù),分析了石墨中雜質(zhì)元素的種類含量及物相組成。石墨中含有Si、Al、Fe、Mg等灰分元素,這些元素大部分以氧化物的形式存在。通過物相分析,了解到這些灰分元素的主要物相組成為游離石英(Quartz)、莫來石(Mullite)赤鐵礦(Hematite)等。石墨中的礦物灰分顆粒夾雜分布于碳顆粒之間,還有一小部分浸染在碳基體中。這些雜質(zhì)在物化性質(zhì)上都有別于碳顆粒,簡單的物理提純方法難以使二者分離,化學(xué)浸出法更有利于石墨雜質(zhì)的去除。探索石墨濕法提純反應(yīng)中的熱力學(xué)規(guī)律,據(jù)此繪制了幾種主要雜質(zhì)元素水溶成分的lga-pH圖,在不同溫度時(shí)的Al-Si-H2O系的φ-pH圖。從生產(chǎn)工藝上分析研究了氫氧化鈉和硫酸的濃度、浸出溫度,液固比、浸出時(shí)間等幾種實(shí)驗(yàn)因素對石墨提純的影響。初步確定了本試驗(yàn)的最佳工藝參數(shù)：高壓堿浸：粒度300目；溫度200℃; NaOH濃度15%；保溫時(shí)間30min；液固比10：1；自蒸汽壓2.1MPa；酸浸：粒度300目；溫度90℃;H2SO4濃度12%；保溫時(shí)間30min；液固比10：1。在上述最佳的工藝條件下提純石墨,固定碳含量達(dá)到了98.71%,雜質(zhì)含量為1.29%,雜質(zhì)脫除率率超過93%,其中Si、Al去除率87%,Fe去除率90%,Ca脫除率95%,Na、Mg脫除率98%。
[Abstract]:Graphite has many excellent physical and chemical properties because of its unique crystal structure. High purity graphite is used as a deep processing product of graphite in advanced seal, composite material, nuclear industry, In this paper, the structure and properties of graphite and the application of graphite are summarized. This paper points out the contradiction between the rapid development of some important industrial departments and the shortage of high quality graphite, summarizes the present situation of purification technology and industrial production of graphite in the world, and puts forward the research direction of preparing high grade graphite from natural flake graphite concentrate. Finally, the main research contents and significance of this paper are put forward. The natural flake graphite concentrate provided by Qingdao Rilai Graphite Co., Ltd is taken as the research object. The existing state of ash impurities in flake graphite and the thermodynamics of ash removal process were studied. According to the thermodynamics, the technical route of purifying graphite by high pressure alkali leaching combined with atmospheric pressure acid leaching method was put forward. Some reaction mechanisms of the purification process were theoretically analyzed. By using modern analytical and testing techniques, the content of impurity elements and the phase composition of impurities in graphite were analyzed. Most of these elements exist in the form of oxides. By phase analysis, it is found that the main phases of these ash elements are free quartz quartzt, mullite hematite, etc. The mineral ash particles in graphite are distributed between carbon particles. There is also a small amount of soaking in carbon matrix. The physical and chemical properties of these impurities are different from those of carbon particles, and it is difficult to separate them by simple physical purification methods. The chemical leaching method is more favorable to the removal of graphite impurity. The thermodynamic law of graphite wet purification reaction is explored, and the lga-pH diagrams of several main impurity elements in aqueous solution are plotted accordingly. 蠁 -pH diagram of Al-Si-H2O system at different temperatures. The concentration of sodium hydroxide and sulfuric acid, leaching temperature, liquid-solid ratio were analyzed and studied. The effects of leaching time on graphite purification were preliminarily determined. The optimum technological parameters were determined as follows: high pressure alkali leaching: particle size 300 mesh; temperature 200 鈩，

本文編號：1542362